Variable resistance device



Nov. 24, 1953 3 GREENE 2,660,652

VARIABLE RESISTANCE DEVICE Filed Oct. 15, 1952 FIG. 1

IN V EN TOR.

S/D/VEV P. GREENE BY Patented Nov. 24, 1953 VARIABLE RESISTANCE DEVICE Sidney R. Greene, New Haven, Conn., assignor to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Application October 15, 1952, Serial No. 314,922

9 Claims. (01. 201-55) This invention relates to control devices for electrical circuits and more particularly to a variable resistance device for making iine resistance adjustments.

An object of the present invention is to provide a novel variable resistance device of simple construction, and of few parts, for making fine resistance adjustments.

The present invention, therefore, contemplates a novel variable resistance device which comprises a resistance wire of predetermined length, and arranged in the form of a loop. Means are provided for twisting the wire to form a plurality of loops to thereby change the effective length of the wire, and the efiective resistance of the device.

The above and other objects and advantages of the present invention will appear more fully hereinafter from a detailed description which follows, taken together with the accompanying drawing wherein one embodiment of the invention is illustrated.

In the drawing;

Figure 1 is a view, partly in section, of one form of a variable resistance device embodying the present invention; and

Figure 2 is a View, partly in section, of the variable resistance device of Figure 1, showing in particular, the resistance wire partly twisted.

Referring now to the drawing for a more detailed description of the present invention and more particularly to Figure 1 wherein one embodiment hereof is clearly illustrated, a variable resistance device, generally designated by the numeral ll, comprises a cylindrical container 12 of suitable material, preferably insulating material, and has an end wall l4. Arranged within container i2 and supported in the form of a loop is a flexible resistance wire it, of predetermined length, which has the ends thereof connected in any suitable manner, such as by soldering, to a pair of terminals i8 secured to end Wall I4. Terminals it may have conductors (not shown) connected thereto for including device H in an electrical circuit, or, the terminals may be of a plugln type for insertion into a socket.

Engaging the wire it at the mid-point thereof is a hooked end 2b of a coil spring 22 which maintains the wire taut. The other end 2 1 of spring 22 is hooked through an opening formed in a projecting part 26 of a rotatable and adjustable member 28 which has a knurled finger-gripping portion 36 of suitable insulating material. Member 28 has an externally threaded portion which cooperates with an internally threaded portion of container l2, adjacent the open end thereof.

2 When portion to is operated, member 2a is moved axially and rotated from the position shown in Figure 1, to effect twisting of Wire id. Engagement of portion 36 with the open end of container 12, prevents excess axial movement of member 23 in one direction, and a stop (not shown), provides for limited axial movement of the member in the opposite direction.

Resistance wire it, as seen in Figure 1, has a single loop, and therefore, will provide the highest resistance when device I i is connected into a circuit. To vary the effective length of wire it and thus the effective resistance to be inserted into the circuit, adjustable member 28 is rotated, to twist the wire so as to form additional loops therein (Figure 2). The length of wire, included in the loops formed by the contacting portions of wire, is short-circuited so that the effective resistance of the device is decreased as the number of loops is increased. It now may be understood that the effective length of resistance wire it and the effective resistance of the device are both a function of the number of loops formed.

From the foregoing, it is apparent that the present invention provides a novel variable resistance device wherein a resistance Wire, which may be twisted in a plurality of loops, provides a device of simple construction and few parts for making fine resistance adjustments.

Although one embodiment of the invention has been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes can be made in the design and arrangement of the parts Without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art.

I claim:

1. A variable resistance device of the class described comprising an electrical conductor, means sup orting the conductor in the form of a loop, and means engaging said loop for providing one or more additional loops in said conductor to thereby vary the effective resistance of the device.

2. A variable resistance device of the class described comprising an electrical conductor, means supporting the conductor at two points for arranging the conductor in the form of a loop, and means engaging said loop for providing one or more additional loops in said conductor to thereby vary the efiective resistance of the device.

3. A variable resistance device of the class described comprising an electrical conductor of predetermined length, means supporting said conductor to form a pair of leg portions, and

means engaging said conductor for providing twining of said leg portions to change the efiective length of the conductor to thereby vary the efiective resistance of the device.

4. A variable resistance device of the class described comprising an electrical conductor, means supporting said conductor in the form of a loop, and means engaging the mid-point of said loop for providing one or more additional loops in said conductor to thereby vary the effective resistance of the device.

5. A variable resistance device of the class described comprising an electrical conductor, means supporting said conductor in the form of a loop, means engaging said loop, and means providing relative movement between both said supporting and engaging means for providing, one or more additional loops in said conductor to thereby vary the effective resistance of the device.

6. A variable resistance device of the class described comprising an electrical conductor of predetermined length, means fixing the ends of said conductor relative to each other and supporting the latter in the form of a loop, and

means engaging said loop for providing one or more additional loops in said conductor to thereby vary the effective resistance of the device.

'7. A variable resistance device of the class described comprising an electrical conductor, means supporting said conductor in the. form of a. loop,

4 means engaging said loop for maintaining the conductor taut, and means connected for operating said last-named means for providing one or more additional loops in said conductor to thereby vary the efiective resistance of said device.

8. A variable resistance device of the class described comprising an electrical conductor, means fixing the ends of the conductor relative to each other and supporting the latter in the form of a loop, resilient means connected to the mid-point of the conductor and maintaining the conductor taut, and. means connected for operating said resilient means for providing one or more additional loops in. said conductor to vary the effective resistance of the device.

92 A variable resistance device of the class described comprising a container, an electrical conductor arranged in the form oi loop Within the container and having the ends thereof fixed to a wall of said container, resilient means engaging the mid-point of said conductor for maintaining it taut, and an adjusting member movably mounted in the container and connected for operating said resilient means for providing one or more additional loops in said conductor to thereby vary the effective resistance of the device.

SIDNEY R. GREENE.

No references cited} 

